As a gas sensor for detecting the concentration of a specific gas component (such as oxygen or NOx) in an exhaust gas of an automotive vehicle etc., there is known a gas sensor having a gas sensor element equipped with a solid electrolyte body. One such type of gas sensor is known, including a gas sensor element having a cylindrical element body and an outer electrode formed on an outer surface of the element body and a metal shell surrounding a radially outer circumference of the gas sensor element to hold therein the gas sensor element (see e.g. Patent Document 1).
As shown in FIG. 12, for example, a gas sensor element 3 has an element body 3s formed with a radially outwardly protruding flange portion 3a; and a metal shell 1000 has a tapered seat portion 1000e formed on an inner surface thereof to hold the gas sensor element 3 by indirect contact of a front end-facing surface 3af of the flange portion 3a with the seat portion 1000e. An annular plate-shaped metal packing 12 is arranged between the seat portion 1000e of the metal shell 100 and the flange portion 3a of the gas sensor element 3 (see FIG. 12(a)) and is deformed along the seat portion 1000e by crimping a rear end portion of the metal shell 1000, with a filling material 6 filled between the gas sensor element 3 and the metal shell 1000, and thereby allowing the filling material 6 to push the flange portion 3a of the gas sensor element 3 toward the front end side (see FIG. 12(b)).